1. Field of the Invention
The invention relates to a continuously lockable adjustment device for the immobilization of structural elements movable relative to one another, with a cylinder which has two working spaces separated from one another by means of a piston and is filled with a working fluid and in which the piston can be displaced axially. In the event of the displacement of the piston, working fluid can be transferred from one working space into the other working space. A piston rod connected to the piston is guided, sealed off, out of the cylinder on one end.
2. Description of the Related Art
An adjustment device of this type as a door immobilizer for motor vehicles is known. It has a cylinder which is filled with a fluid and on the inner wall of which a piston connected to a piston rod is guided in a sealing-off manner. The cylinder inner space is subdivided into two working spaces, and a locking valve actuable from outside and having a releasing tappet led through the piston rod is provided for locking in a desired position. On account of this, the adjustment device is of complicated construction and has a large number of components.
A further known adjustment device is a continuous hydraulic door immobilizer for motor vehicle doors, which has a cylinder and a piston rod movable relative to the cylinder. In the cylinder, two working chambers are separated from one another by means of a separating piston having connecting ducts which allow the flow of an oil from one working chamber into the other working chamber. The connecting ducts, which are arranged laterally in the separating piston traversed centrally by the piston rod, are provided with valves which are closed when the adjustment device is in the state of rest. The piston rod is mounted on each of the two sides of the separating piston in a sealing and guiding system, respectively. Such an adjustment device not only has a comparatively high weight, but also requisite complicated sealing-off.